When using message += string, my code fails. But when I use message = message + string, it works. Why?

Question

This has happened multiple times with multiple sets of code. Occasionally I'll be having getting my javascript code to run, so I double and triple check it, make sure it's the same as the video, and look at the questions about the module and do googling. However, it always seems to be OK. I have found, though, that if I have something like:
message += string
and I change it to 
message = message + string
my code will then work. I'm not even sure how I figured out that was my problem the first time it happened, but it's come up enough times now that I figure I should do something about it. I'm using Chrome running Windows, if that makes a difference for some reason. Any help would be appreciated, thanks.

Billy Bellchambers · Answer

Hi Joseph,
I am a bit confused where you could be going wrong with your concatenation based on the description above.
As you have rightly said.
```javascript
var message;
message += string;
message = message + string;
```
Both of these things are exactly the same.
Have you got some working examples you could share maybe we could get to the root cause with those for you. Operating system and browser shouldn't affect how these run for you, least not from my experience.
Without specific examples I can only offer a few generic pointers:
1. Ensure you have already previously defined your variables you wish to concatenate.
2. Make sure your strings are contained within quote marks. "string".
3. Don't forget your closing statement semi-colon.
Hope if nothing else these pointers are a little helpful.
Otherwise I am sure with an example we might be able to shed some more light on the issue.
Happy coding!

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Joseph Hess

Joseph Hess

When using message += string, my code fails. But when I use message = message + string, it works. Why?

1 Answer

Billy Bellchambers

Billy Bellchambers